and have a better client/customer relationship..
----- Original Message -----
From: Dave Chapman <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, August 15, 2002 11:49 AM
Subject: Re: [TN] Conformal coating on top of plastic IC's
> Our experience is that if that is what the Customer wants, the Customer
> gets. Whether it is needed or not. As long as the joints are covered that
> will be sufficient (technically). IPC loosely states that everything
> specified to be covered needs coverage. Our method of operation here says
> coat everything thus creating no questions from the customer even if you
are
> correct about moisture not being a factor after assembly. Our approach is,
> if customer is trainable then work with them to educate them. Educate
rather
> than argue. You will both appreciate the experience.
> Dave Chapman
> CSI
>
> -----Original Message-----
> From: Graham Naisbitt [mailto:[log in to unmask]]
> Sent: Thursday, August 15, 2002 8:43 AM
> To: [log in to unmask]
> Subject: Re: [TN] Conformal coating on top of plastic IC's
>
>
> > Dear Technetters,
> >
> > We've just finished our first few boards with Humiseal 1B31 conformal
> > coating, applied with a selective spraycoating machine, and we asked the
> > customer to inspect the products.
> > He commented that some areas on top of the IC's were not covered
> > completely, which is required (so he says) because these are plastic
> > components which may absorb moisture if left uncovered.
> >
> > I'm not gonne argue about this with the customer, but still I'm
> > interested to hear from you wether the fact that the IC's are plastic is
> > indeed a reason to require them to be completely covered with coating.
> > As far as my knowledge goes the problem with plastic IC's and moisture
> > is limited to the soldering process only, but I may be wrong.....
> > Anyone can comment ?
> >
> > Daan Terstegge
> > Unclassified mail
> > Personal Website: http://www.smtinfo.net
>
> Daan,
>
> I suspect that the reason for the lack of coverage to the IC covers is due
> to dewetting. The dewetting will probably be caused by the presence of
some
> mould release residues. Is this a problem?
>
> Not really, although it would be a good idea to try and obtain IC's that
do
> not exhibit this problem, as it may be that if you clean the assembly, and
> the mould release is silicone, then you might be spreading the silicone
over
> the surface of the assembly.
>
> Is this a problem? Yes. Inspect under UV and check for dewetting in other
> areas.
>
> As to the issue of component reliability due to moisture ingress, this is
> highly unlikely with the IC. However the customer is right to require it
for
> the reason I just outlined. It should not happen...
>
> Hope this helps
>
> Regards, Graham Naisbitt
> --
> [log in to unmask]
>
> Concoat - Engineering Reliability in Electronics
> Concoat Systems - Measuring Electronics Reliability
> Synergie - Electro-chemically compatible process chemistries
>
> Concoat Limited
> Alasan House, Albany Park
> Camberley, GU16 7PH - UK
>
> Phone: +44 (0)1276 691100
> Fax: +44 (0)1276 691227
> Mobile: +44 (0)79 6858 2121
> Web: www.concoat.co.uk & www.concoatsystems.com
>
> --------------------------------------------------------------------------
--
> -----
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
> [log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> ext.5315
> --------------------------------------------------------------------------
--
> -----
>
> --------------------------------------------------------------------------
-------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
> --------------------------------------------------------------------------
-------
>
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
